1. Field of the Invention
This invention concerns mono-core type microcapsules coated with waxes and a process for producing them.
Mono-core type microcapsules coated with waxes of this invention are utilized in all sort of industrial fields for medicines, foodstuffs, feeds, fertilizers, chemical products and the like.
2. Description of the Prior Art
Microcapsules have hitherto been produced by 14 types of methods as described in "Chemical Engineering of Japan", vol. 46, No. 10 (1982), on page 548.
These microcapsules are now utilized in all sort of industrial fuels for foodstuffs, medicines, agricultural agents, feeds, perfumes, enzymes, activated carbon and the like as described in the literature cited above. Among the 14 types of the production processes for the microcapsules aforementioned, aerial suspension process (fluidizing bed coating) and melt-dispersion-cooling process (spray and coagulating pelletization) have been known as typical examples for the method of depositing waxes to particles.
However, the former process, since the fluidizing bed is used in, particles as the core material are liable to be destroyed and no intact membranes can be formed because of the flaky shape of the membrane. Further, a great amount of waxes have to be used for forming the intact membrane.
Further, in the latter process, since the core material is added into the molten waxes, the core material is thermally denatured and a lot of waxes are required as well. Furthermore, the core material is localized in the wax or the core material is contained in the form of a plurality of particles in a wax particle to form multicored capsules. Accordingly, adequate microcapsule function can not be attained depending on the application uses, for example, in the case of fish feeds.